The Ceramic Gas Lens Nozzle (T26) No 6 54N16 is a type of welding nozzle that is used to improve the flow of shielding gas during the welding process. It is made of ceramic and has a small hole in the centre that allows the shielding gas to flow through. The nozzle is designed to create a laminar flow of gas around the welding arc, which helps to protect the weld from contamination.